Using Bandsaw to Square up timber?

[MikeJhn]

Looking at the picture of the cut, its noticeable that the belly of the timber is above the fence, also the cut from the cupping is above the fence, therefore the majority of the dust thrown left, IMO is from the blade itself due to the set of the teeth and the bottom of the cupping being above the fence.

I have on occasions to prove where the dust is coming from stopped the blade half way through a cut and inspected inside the top and bottom wheel housing to see how much dust/chips etc is being carried around in the blade gullet, In all of my inspections there has been practically none, I do have good condition brushes in the housing and decent (2000M3/hr) extraction in the bottom wheel housing, so my conclusion is that the dust I experience on the top of the table on my bandsaw is from the blade/cut itself, hence the extraction above the table, saying all this, I will try Eric's solution and put the extract below the table to see if that makes any difference, although the solution I am using at the moment seems to be a very good one.

Mike

 

[MikeJhn]

Powertools wrote:

Please can we all get to a situation where we can all agree that not all bandsaws are the same. This often promoted idea that the gullet of the blade needs to run in the centre of the wheels of all saws is misleading to say the least.

Can you enlighten me as to when this is misleading? Since following the Alex Snodgrass video on setting up my bandsaw, both my desktop and my 14" have behaved significantly better.

Mike

 

[Alexam]

It's not the case with larger blades. A 3/4" blade would not be run with the teeth in the centre as it would be over the wheel. Smaller blades are what Alex Snodgrass was referring to.
Malcolm

 

[CHJ]

Can you enlighten me as to when this is misleading? Since following the Alex Snodgrass video on setting up my bandsaw, both my desktop and my 14" have behaved significantly better.

Mike

Bandsaw behaviour can be totally different on machines with crowned wheels to those with flat wheels, setup procedure needs to be selected to suit what works with your particular machine and wear state.
The Snodgrass method is not appropriate for my machine, it won't achieve a working setup.

 

[Alexam]

Please correct me if I am mistaken, but Chas usually uses a larger blade for cutting blanks. We both have the same Record BS400 bandsaw but the Alex Snodgrass method is only appropriate for smaller blades, which I mainly use.

Small blades can get the teeth in the centre of the top wheel.

Malcolm

 

[CHJ]

Malcolm, I think you need to loose the fixation on blade/wheel location, the important criteria are the ninety degrees fore and aft to the table and parallel to the mitre slot.
I regularly use 1/4 inch blades on my SIP machine but I personally take no notice of where it runs on the wheel as long as it runs true to the table.

 

[Eric The Viking]

I'm posting this mainly because I don't want to waste it. Chas (typically!) summed up what I was going to say, whilst I was drawing the diagrams...

There are different forces at work, but the overall effects and behaviour in these cases will be much the same for big and small blades.
Big blade: (A & B) lots of tension. When you put the teeth near the top of the crown of the wheel, the centre of force is behind the teeth, and it pulls the blade onto a skew (green line). Under those circumstances it will flutter a lot, as it's trying to climb back up the crown, but can't easily. It's being forced into a cone shape round the wheel(s), but wants to be a cylinder. This is one reason why a flutter test can be misleading, IMHO.

If you run the blade so that it's parallel to the table ( (b.) I haven't drawn the green line in, but it's pretty obvious where it would be), the forces balance when the blade describes part of a cylinder (not a cone), and it's got minimal incentive to flutter and will run true by default). The blade guides, in particular the back rollers or blocks, will stop it from deviating from that.

On my own saw, the "right" setup for the 5/8" blades (biggest I can usefully tension) is pretty much as the red outline: the tooth tips actually do scuff the aluminium rim, or even hang over the leading edge of the wheel. It _will_ be different for other machines, but the general idea holds good.

Small blades: (C & D) same outcome but for different reasons: In this case, because there is less metal, the blades can twist a lot more easily. So the set of the teeth pushing into the rubber of the tyre cause it to twist. I don't possess any really small blades at the moment , but the smaller ones I do have (about 1/4") exhibit this behaviour.

If I track them lower down the crown, towards the front, this tends to sort itself out...

Hope that helps to explain why we disagree with Mr. Snodgrass on this (at least, I think we do!).

E.

 

[Jacob]

Bandsaw no good for ripping unless it's either very small stuff or it's a huge industrial machine. You can use it a few times but they blunt very quickly and start wandering off. Better for cross cutting and just odd jobs rather than a production machine like a circular saw which keeps on going.
If you are worried abt a TS use two push sticks. Use two push sticks even if you aren't worried - because you should be!

 

[Eric The Viking]

Bandsaw no good for ripping unless it's either very small stuff or it's a huge industrial machine. You can use it a few times but they blunt very quickly and start wandering off.

I cannot imagine how you jump to that conclusion, unless you mean when using the wrong sort of blade... in which case, you really ought to say so.

 

[MikeJhn]

All interesting stuff guys and lots of theory, but I have found in practice that my 350S responds to the Snodgrass idiom, never had a bandsaw run so well, can see no reason to change from it, until maybe I get a different bandsaw and find the set up I use does not work, but thanks for the explanations, most enlightening.

Mike

 

[powertools]

Powertools wrote:

Please can we all get to a situation where we can all agree that not all bandsaws are the same. This often promoted idea that the gullet of the blade needs to run in the centre of the wheels of all saws is misleading to say the least.

Can you enlighten me as to when this is misleading? Since following the Alex Snodgrass video on setting up my bandsaw, both my desktop and my 14" have behaved significantly better.

Mike

I think others have answered your question. The truth is that not all bandsaws are the same. I have a Kity 613 and an Inca and both would not work using the set up method so heavily prometed by the so called experts.
If it has worked for you that's good but there will be many others searching the internet for advice and will come across this thread and think they have found the solution to their problems but depending on the machine they have they could actually make things worse.

 

[Jacob]

Bandsaw no good for ripping unless it's either very small stuff or it's a huge industrial machine. You can use it a few times but they blunt very quickly and start wandering off.

I cannot imagine how you jump to that conclusion, unless you mean when using the wrong sort of blade... in which case, you really ought to say so.

I've been using a Startrite 352 for about 40 years and must have got through 1000s of blades including all shapes and sizes.
A new blade carefully set up will rip perfectly, but as I said above you can use it a few times but they blunt very quickly and start wandering off. I'm talking about a busy workshop here (well it was back then!). Maybe not a noticeable issue with just a bit of weekend DIY
TS a totally different animal. If stuff too deep to rip with a TS then it's handy to do a deep cut both sides as far as poss and then pass it through the bandsaw to take out the middle. The TS is very reliably accurate and the use of band saw is reduced and guided by the TS cut.

 

[Phil Pascoe]

More than a blade a week for forty years? :shock: hell!

 

[Jacob]

More than a blade a week for forty years? :shock: hell!

40 x 52 = 2080
Oh alright I haven't actually counted them but what I do know is that you get through them very quickly - yes more than a blade a week - if you try to use a bandsaw in a production way, rather than saving it for the jobs where it is essential. Definitely several 100s!
TS blades last years, can be sharpened, can have new tips brazed on. As a result I buy them only occasionally, one at a time, some have been in the workshop for years.
BS blades are disposable - unserviceable, short lived and I typically bought them 5 or 10 at a time, several times a year (when I was hard at it). It's an expensive machine to run.

 

[ColeyS1]

Try m42 blades Jacob ffs

Sent from my SM-G900F using Tapatalk

 

[Jacob]

Try m42 blades Jacob ffs

Sent from my SM-G900F using Tapatalk

Yes they last longer but cost more.

One plus with the old hardpoint is that they are re-sharpenable (if you can get your saw doctor to do it) but won't necessarily cut straight - so get used for firewood, or recycling old wood where there may be nails

 

[custard]

I use Tuffsaws M42 blades. The bandsaw is used pretty much every day, including regularly ripping 8 or 10" wide veneers in really difficult timbers like Rosewood. Each blade lasts me months and months. In fact I often end up replacing them even when they're still cutting well, just because I've convinced myself the blade must have slowly been losing performance and I haven't noticed it. But when the new blade goes on there's absolutely no performance difference!

I honestly believe that a middle aged hobbyist who switched to an M42 blade might never need to replace it!

There are however some downsides to M42. The finish isn't the smoothest, it's not exactly rough but if you use your bandsaw for joint cutting it might not be your best choice. The kerf is pretty wide, which means you lose timber as waste and you need a fairly powerful motor to maintain feed rates. And the blade is also thicker than normal, so tensioning might be a problem on a lightweight machine.

But if you can accommodate these restrictions then M42 makes a huge amount of sense.

 

[Phil Pascoe]

Plasterboard screws knacker them though. Damhikt.

 

[Jacob]

I use Tuffsaws M42 blades. The bandsaw is used pretty much every day, including regularly ripping 8 or 10" wide veneers in really difficult timbers like Rosewood. Each blade lasts me months and months. In fact I often end up replacing them even when they're still cutting well, just because I've convinced myself the blade must have slowly been losing performance and I haven't noticed it. But when the new blade goes on there's absolutely no performance difference!

I honestly believe that a middle aged hobbyist who switched to an M42 blade might never need to replace it!

There are however some downsides to M42. The finish isn't the smoothest, it's not exactly rough but if you use your bandsaw for joint cutting it might not be your best choice. The kerf is pretty wide, which means you lose timber as waste and you need a fairly powerful motor to maintain feed rates. And the blade is also thicker than normal, so tensioning might be a problem on a lightweight machine.

But if you can accommodate these restrictions then M42 makes a huge amount of sense.

Interesting! What size blades do you use on 8, 10" timber?
I have used them, they are good, but not that good, in my experience. Maybe I need to look again.